Exploring prognostic and predictive response therapy factors in cancer disease is one of the most exciting issues of modern oncological science. Targeting intracellular signalling molecules is one of the novel approaches in which basic and translational researches meet clinical practice to define the best management of malignancies. The goal for target therapies is to identify agents that target tumor-specific molecules, thus sparing normal tissues. Those molecules are called biomarkers, and their identification is recommended for correct therapeutic planning. Hence, the contribution of clinical and surgical pathology to define cancer prognostic groups and treatment responsive tumors is essential not only for the efficacy of the cures, but also for ethical, economical, and social reasons. The promises of tailored (personalized) therapy are now almost certainly realistic and can give concrete hope to many cancer patients in the world. In this book, we have tried to describe the "state of art" in these fields of oncology, specifically considering prognostic and predictive response therapy factors in colorectal, breast, lung, gastric, renal, liver and prostate cancers.